In the prior art, photosensitive protective films for semiconductor devices and photosensitive insulating films for multilayer printed circuit boards are formed of photosensitive polyimide compositions, photosensitive epoxy resin compositions, photosensitive silicone compositions, and the like. As the photosensitive material applied for the protection of such substrates and circuits, Patent Document 1 discloses a photosensitive silicone composition. This photosensitive silicone composition is curable at low temperature and forms a coating which is flexible and fully reliable with respect to moisture resistant adhesion and other properties, but is less resistant against chemicals such as photoresist strippers having a high dissolving power, typically N-methyl-2-pyrrolidone (NMP).
To overcome the problem, Patent Document 2 proposes a photosensitive silicone composition based on a silphenylene structure-bearing silicone polymer. This composition is improved in chemical resistance against photoresist strippers and the like, but still has the problem that the cured coating peels from the substrate or cracks in a thermal cycling test (repeating 1,000 cycles a test of holding at −25° C. for 10 minutes and holding at 125° C. for 10 minutes). A further improvement in the reliability of such resin compositions is desired.